Pump



Sept. 1,3, 1966 Q R STOELT|NG HAL 3,272,132

PUMP

Filed Aug. 5, 1964 lNvENToRS CARL E. STOELUNG EARL M. STECKER ATTORNEY United States Patent O 3,272,132 PUMP Carl R. Stoelting and Earl M. Stecker, Kiel, Wis., assignors to Stoelting Brothers Company, Kiel, Wis., a corporation of Wisconsin Filed Aug. 3, 1964, Ser. No. 386,964 4 Claims. (Cl. 103-9) This invention relates to a pump for delivering liquid and air in a desired ratio and has particular application to delivering a mix of air and liquid mix to the freezing cylinder of freezers of the type used in manufacture of ice milk, ice cream, sherbet, frozen custard, etc.

In `soft serve freezers it has `long been customary to add air to the liquid mix to be incorporated in the product. One type of freezer incorporates this added air by means of a beating action during the freezing process but this is difficult to control and the amount of air added to the end product is subject to considerable variation. Another type of freezer incorporates a positive pressure freezing cylinder and the blend of air and liquid mix is delivered under lpressure to the cylinder. Much effort has been directed to the provision of various types of pumps for the liquid and air to accurately control the ratio of the two. The problem is complicated somewhat by the fact that the entire pump must permit of complete disassembly for cleaning and inspection purposes.

The principal object of this invention is to provide a simple pump capable of accurately blending a liquid and air to obtain a desired ratio. A further object is to provide such a pump which will meet all the sanitary requirements imposed upon such equipment.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, .as will obvious modifications of the single embodiment shown in the drawings, in which:

FIG. l is a vertical section through the present pump; and

FIG. 2 is an end view taken Vas indicated by line 2-2 on FIG. l.

The pump housing or body is basically made `up of three principal parts, the left-hand portion being the cylinder head 10, the middle or cylinder portion 12, and the right-hand portion 14 containing valving, inlets and outlets. The right-hand portion of the body is provided with an air inlet fitting 16 which is provided with a peripheral groove containing an O-ring 18 and is inserted in the cooperating smooth bore aperture lin the body portion and retained therein by means of a cross-pin 2t) which captures a portion of the -upper peripheral groove 22. The fitting 16 is provided with an O-ring valve seat 24 against which the ball type check valve 26 seats under influence of the compression spring 28 seated on the shoulder leading Vto the passage 30. Passage 30 leads to the passage 32 in this body portion and this, in turn, communicates with passage 34 in the cylinder portion with the passage 34 running parallel to the cylinder 36 up through passage 88 in the cylinder head and into the left-hand end of the cylinder. Passage 32 also communicates with the crossbore 38 in fitting 4G which is mounted in a cooperating smooth bore in the right-hand body portion 14 with O- ring seals both above and below the cross-bore 38. The lower end of the axial bore 41 terminates in an O-ring valve `seat 42 against which the ball check valve 44 seats under influence of spring 46. The upper end of the axial bore 41 leads to the adjustable bleed valve 48 and the air which is bled past this valve can escape through passage 50. The position of the bleed valve 48 is adjusted by turning knob 52 and may be retained in a set position by tightening the set screw 54.

As the piston 56 travels to the right in cylinder 36 ball check 26 will open and air will be drawn in through the ice air inlet and into the left-hand end of the cylinder, When the piston `starts moving to the left the inlet check valve 26 will close and the outlet cheek valve 44 will open but some of the air will be bled out past the bleed va-lve 48.

The right-hand body portion 14 of the pump housing is also provided with a liquid inlet fitting 58 which is similar in construction to the air inlet fitting 16 in that it has an O-ring seal 60 and is retained in position by means of a cross-pin 62 capturing a portion of the peripheral groove. The inner end of the liquid inlet fitting 58 is also provided with a-n O-ring valve seat against which the check valve 64 will seat under influence of spring 66. As the piston 56 moves to the left liquid will be drawn past the check valve 64 into the cylinder 36. When the piston starts moving to the right this check valve will seat but the outlet check valve 68 will be moved ofr its seat 70 carried by insert 72 which is held against the shoulder in the cooperating cavity by means 4of the projecting annular portion of the cylinder wall (as may be seen in FIG. 1) which also locates the parts in alignment. Therefore, :liquid is delivered under pressure past the check valve 68 to the chamber 74 to which chamber the air is also delivered under pressure. This chamber is provided with a common outlet duct or fitting 76 for delivering the liquid and air in the `desired ratio with this ratio being determined by the amount of bleed past valve 48. If valve 48 is closed, then you will get the maximum amount of air in the mix. Since air is pumped on the r-od side of the piston the maximum air can be controlled by the diameter of the rod.

The bleed valve fitting 40 is retained by means of a cross-pin 78 which passes through a suitable .slot in the fitting and it should be noted that this slot would run tangential to the radius of the tting so as to insure alignment of the cross-bore 38 with passage 32. lf desired, however, the slot could be replaced by means of a peripheral groove as with the inlet and outlet fittings previously described but in this case a peripheral groove would have to be provided around the cross-bore to insure communicating passages no matter what the position of the bleed fitting might be.

It will be noted that the fittings 16, 58, `and 40 :can all be withdrawn simply by removal of their corresponding cross-pins. This simplifies cleaning and inspection.

,Since there are no threads the entire unit can be thoroughly cleaned and inspected, there being no blind holes in the present construction.

The cylinder portion 12 is sealed with respect to the right-hand housing portion 14 by means of O-rings 80, 82. The joint between the cylinder head and the cylinder is provided with la suitable gasket 84 -and Iit will be noted that a locating pin 86 is used to insure proper orientation of the passage 88 in the cylinder head with the passage 34. The cylinder head includes a tubular portion provided with two O-ring seals 90, 90 through which the piston rod 92 passes. This tubular portion also serves to mount the clamping nut 94 which is provided with external threads upon which the yoke 96 is mounted. The yoke is provided with suitable jaws 98, 98 which are adapted to pass over the reduced diameter portion of assembly rods 100 and when it is desired to clamp the pump in assembled position the nut 94 is rotated to cause the yoke to ba-ck off to the left until it seats firmly, as illustrated in FIG. l, against the right-hand shoulder of the head 102 of the assembly rods. The right-hand end of the assembly rods can either be fixed on a plate of the freezer as represented by line 104 or can be mounted on a separate plate, the important thing being to provide 1a plate against which the yoke can be drawn up to tighten the whole assembly into a sealed relationship and yet allowing rapid disassembly of the entire unit for cleaning.

Conceivably it would be possible to throttle the air inlet instead of bleeding from the air outlet but it is preferred to bleed from the air outlet since at this point you are dealing with higher air pressure and, hence, this is a more reliable type of control than trying to starve the pump at very low pressure values which could lead to considerable error or uctuation.

Although but a single embodiment of the present invention has been illustrated and described, it wi-ll be apparent to those skilled in the art that various changes and modiications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

We claim:

1. A pump for proportioning air and liquid comprising a housing having a cylinder therein, a piston reciprocable in said cylinder, liquid inlet and outlet means communicating with one side of the piston, air inlet and outlet means communicating with the other side of the piston, check valves in said inlet means and said outlet means, and a bleed valve -in the air outlet means upstream of the check valve lmeans associated therewith, each inlet means and the air outlet means comprising a fitting retained in a smooth bore cavity in the housing and provided with a seal, the inner end of each iitting being provided with a v-alve seat, said housing comprising two principal portions, one portion containing the inlet and outlet fittings and the other portion including the cylinder, seal means between the portions and compression means holding the portions together, the check valve means in the liquid outlet means including a seat assembly in said one housing portion communicating directly with the one end of the -cylinder and retained in position by said other housing portion.

2. A double acting pump for pumping gas and liquid comprising a pump housing including a first housing part having a cylinder formed therein, a piston mounted for reciprocation within the cylinder, a second housing part, said first and second housing parts including wall portions disposed in overlying juxtaposed relation, one end of said cylinder opening through the said wall part of said first housing means, a fluid flow passage formed in said first housing part in communication with the opposite end of said cylinder and opening through the said wall portion of said first housing part, said second housing part including first induction and eduction passages in communication with the cylinder on one side of the piston and second induction and eduction passages in communication lwith the cylinder on the opposite side of the piston, check valve means in said first and second mentioned induction and eduction passages respectively, a common discharge passage formed in said second housing part in communication with said first and second eduction passages, and means for securing said housing parts together, one of said eduction passages within said second housing part being provided with an auxiliary discharge port located upstream from the check valve means therein and a bleed valve controlling said auxiliary discharge port.

3. The double acting pump described in claim 2 wherein said first induction .and eduction passages in said second housing part are .in communication with said fluid ow passage and said second induction and eduction passages are in communication with the open end of the cylinder.

4. The double acting pump described in claim 3 wherein said check valve means comprises valved fittings disposed in smooth bores in said second housing and with lone of said fittings retained within its bore by said first housing part.

References Cited by the Examiner UNITED STATES PATENTS 670,796 3/1901 Lynch 103-9 1,322,236 11/1919 Fish 103 9 1,481,358 1/1924 Dwyer 230-46 2,755,739 8/1956 Euwe 103-9 2,765,027 10/ 1956 Trimble 103-6 3,067,987 12/.1962 Ballou et al. 223-318 3,178,888 4/1965 Hampton 103-9 3,180,106 4/1965 Brandt et al 62-177 FOREIGN PATENTS 643,558 3/1928 France.

958,171 5/1964 Great Britain.

MARK NEWMAN, Primary Examiner.

SAMUEL LEVINE, Examiner.

W. L. FREEH, Assistant Examiner. 

1. A PUMP FOR PROPORTIONING AIR AND LIQUID COMPRISING A HOUSING HAVING A CYLINDER THEREIN, A PISTON RECIPROCABLE IN SAID CYLINDER, LIQUID INLET AND OUTLET MEANS COMMUNICATING WITH ONE SIDE OF THE PISTON, AIR INLET AND OUTLET MEANS COMMUNICATING WITH THE OTHER SIDE OF THE PISTON CHECK VALVES IN SAID INLET MEANS AND SAID OUTLET MEANS, AND A BLEED VALVE IN THE AIR OUTLET MEANS UPSTREAM OF THE CHECK VALVE MEANS ASSOCIATED THEREWITH, EACH INLET MEANS AND THE AIR OUTLET MEANS COMPRISING A FITTING RETAINED IN A SMOOTH BORE CAVITY IN THE HOUSING AND PROVIDED WITH A SEAL, THE INNER END OF EACH FITTING BEING PROVIDED WITH A VALVE SEAT, SAID HOUSING COMPRISING TWO PRIN CIPAL PORTIONS, ONE PORTION CONTAINING THE INLET AND OUTLET FITTINGS AND THE OTHER PORTION INCLUDING THE CYLINDER, SEAL MEANS BETWEEN THE PORTIONS AND COMPRESSION MEANS HOLDING THE PORTIONS TOGETHER, THE CHECK VALVE MEANS IN THE LIQUID OUTLET MEANS INCLUDINGG A SEAT ASSEMBLY IN SAID ONE HOUSING PORTION COMMUNICATING DIRECTLY WITH THE ONE END OF THE CYLINDER AND RETAINED IN POSITION BY SAID OTHER HOUSING PORTION. 